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Extension

1960

CC171 Revised 1960 Pasture Weed Control John Furrer Don Burzlaff

Follow this and additional works at: http://digitalcommons.unl.edu/extensionhist Furrer, John and Burzlaff, Don, "CC171 Revised 1960 Pasture Weed Control" (1960). Historical Materials from University of NebraskaLincoln Extension. Paper 3153. http://digitalcommons.unl.edu/extensionhist/3153

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CC-171

1960

PRODUCTIVE PASTURES

Pasture Weed Control

YOU MAY CONTROL WEEDS IN PASTURE:

• •• •

Chemically By Mowing By Reseeding By Management

EXTENSION SERVICE-UNIVERSITY OF NEBRASKA COLlEGE OF AGRICULTURE AND U. S. DEPARTMENT

W. V. lambert, Director E. W. Janlke, Assoc. Director

OF AGRICULTURE COOPERATING

Pasture Weed Control Weed elimination is one of the most important steps you can take toward increasing returns from an unproductive pasture. Each year weeds rob many Nebraska farmers of one-half to three-fourths of the desirable forage some pastures are capable of producing. Weeds use valuable moisture and plant food that could be utilized for producing more forage for extra pounds of beef and milk. Experimental work shows that a piece of land is capable of producing a fairly definite amount of plant growth. If weeds are present in your pasture, there is less moisture and plant food for desirable forage production. Management and care determines whether or not your pasture produces (1) desirable grasses and legumes or (2) weeds at the expense of grass production. ( Methods of Controlling Weeds in Pastures Weeds in pastures can be controlled with chemical weed killers, by mowing, reseeding, and proper management.

Chemical Control Experimental results show we can obtain 75 to 90 % control of most troublesome broadleaf weeds from early June applications of one pound of 2,4-D ester for four successive years. It will be necessary to spray for several consecutive years when ironweed, vervain, and false boneset are present. If your principal weeds are thistles, annual ragweed, asters and gumweed, two years spraying should give excellent control.

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You can kill most annu al weeds with one timely applica tion of the recommended rate of chemical. Som etimes a second spraying is necessary to control late emerging plants. Late September, October or early spring treatments appear to be equall y effective on most fa ll annuals, biennials, and dandelions. ' 1\T e h ave fo und that weeds are most easily killed with herbicides when they are growing rapidly. Good soil moisture, high fertility, and warm temperatures bring about rapid plant grow th which is necessary for good kills with 2,4-D and2,4,5-T. If the plants you are spraying are stunted because of low soil fertility, lack of moisture, or extreme temperatures, they will be difficult to kill. ' 1\T e also have noted that perennial plants which have been mowed or disturbed by disking or plowing shortly before 2,4-D and 2,4,5-T are applied, are more difficult to kill than undisturbed plants. Advantages of Chemical Control 1. One to two years of chemical treatment will eliminate many broadleaf weeds. You will n eed to treat for three or four consecutive years to eliminate 75 to 90% of the har d-to-kill perennial broadleaf weeds. 2. Chemical costs are relatively low; they u sually average $1.00 to $1.50 per acre for the material. 3. On land too steep or rough for mowing or other mechanical treatm ent, spr ays can b e applied by airplane. 4. You can expect increases in forage production after the first year of the trea tment. 5. Commercial application of h erbicides is available in most communities. This makes it unnecessary to invest in equipment and eliminates interfer ence with your o ther farm work. 6. 2,4-D, silvex, 2,4,5-T and amitrol are not poisonous to livestock when used as suggested in this bulletin. Disadvantages of Chemical Control l. Critical periods of application often com e a t the same time you are busy with other farm work. 2. You may need special equipment. However, sprayers are more common on farms now with increased use of insecticides, h erbicides, and liquid fertilizers. 3. Cost per acre may be higher for spraying than it is for mowing. 4. D esirable legumes are los t (if present) as a result of spraying with commonly available 2,4-D compo unds. H owever, you can n ow obtain 2,4-D butyric which can be used on mixtures of gr asses and alfalfa, birdsfoot trefoil, and red clover without serio us injury to the legumes. 5. Weedy grasses are not affected b y commonly used weed sprays .

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Table 1.- Troublesome pasture weeds and recommended chemical control. The letters in parenthesis following each weed indicate if it is an annual (A), fall annual (FA), biennia l ( B), or perennial (P). The amount and kind of chemical to apply and the time to treat is given to the right of each species. You will find the ester forms of 2.4-D are more effective than amine salt on most perennials. Amount and Kind of Chemical Per Acre

Weed

Annual ragweed (A) Asters (P)

\!:! to l lb. 2,4-D l lb. 2,4-D

Beggar's ticks (A) Black nightshade lA) Boneset, False (P)

\!:! to 1 lb. 2,4-D 1 lb. Silvex 1 to 2 lbs. 2,4-lJ

Buckbrush (P) Buffalo bur (A)

1 to lbs. 2,4-D ester Res istant to 2,4-D and 2,4,5-T

Bull thistle (B)

1 lb. 2,4-D before flowering

Burdock (B)

lib. 2,4-D

Bur ragweed (P) Cactus, prickly pear (P)

2 lbs. 2,4-D ester llb. 2,4,5-T ester in 10 gal. diesel fuel applied as wetting spray 1 lb. 2,4-D

Canada thistle (P)

Cocklebur (A) Dandelion (P) Dock (P) Dogbane (P)

2 to 4 lbs. 2,4-D and 2,4,5-T mixture in 100 gal. water \!:! to 1 lb. 2,4-D llb. 2,4-D lib. 2,4-D lib. 2,4-D

Field bindweed (P)

lib. 2,4-D

Fireweed (Kochia) (A) Giant ragweed (A) Goldenrod (P)

\!:! \!:!

Green sagewo rt (P) Ground cherry (P)

1 lb. 2.4-D 1 lb. Silvex

Gumweed (P) Hemp (A) Hoary cress (P)

V2 \!:!

to 1 lb. 2,4-D to I lb . 2,4-D 1 to 2 lbs. 2,4-D

Horse nettle (P) Ironweed (P)

1 lb. 2,4,5-T 1 to 2 lbs. 2,4-D

Jimsonweed (A) Leafy spurge (P)

1 l b. 2,4-D 1 to 2 lbs. 2,4-D

Locoweed (P) Mares tail (A)

\!:! to 1 lb. 2,4-D 1 lb. 2,4-D

Marsh elder (A)

\!:!

Chokecherry (P)

to 1 lb. 2,4-D to 1 lb. 2,4-D I to 2 lbs. 2,4-D

to I lb. 2,4-D

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Time to Treat

Early summer Early summer for 2 or more years Early summer Early summer Mid-summer for 2 or more years May 15 to early June Mow early in spring Late fall on rosettes or in spring before flowering Late fall on rosettes or in spring In June for 2 or more years I n September At early bud; repeat treatment in fall ; treat 2 or more years Late spring or early summer as a wetting spray Late spring Late fall or early spring Late fall or early spring Early spring for 2 or more years At bud stage or in late fall; repeat treatments for 2 or more years Early to late spring Late spring to early summer Early summer for 2 or more years Apply in June Early summer; repeat treatments Late spring or early summer Late spring or early smnmer At bud stage; repeat treatment in fall; treat for two or more years Early summer Late spring; treat for 2 or more years Late spring or early summer At early bud stage; repeat treatment in fall ; 2 or more years Late spring Late spring or early summer for 2 or more years Late spri ng or early summer

Table 1.-Troublesome pasture weeds and recommended chemical control. The letters in parenthesis following each weed indicate if it is a n an nua l (A), fall annual (FA), biennial ( B), or perennial (P). The amount and kind of chemical to app ly a nd the time to treat is given to the right of each species. You will find the ester forms of 2,4·D are more effective than amine salt on most perennials. Amount and Kind of Chemical Per Acre

Weed

Milkweed (P)

8 lb. Amitrol

Mullen (B) Pennycress (FA)

\12

Peppergrass (FA )or (A) Poison hemlock (B) Poison ivy (P) Prickly poppy (A) Puncture vine (A) Ragweed, Perennial (P)

Y2 to l lb. 2,4-D 2 lbs. 2,4-D etser 2 to 3 lb~. 2,4,5-T ester \12 to l lb . 2,4-D \12 to 1 lb. 2,4-D l lb. 2,4·D

l lb. 2,4,5-T to l lb. 2,4-D

Rocky Mt. Bee Plant (A) \12 to l lb. 2,4-D Russian knapweed (P) Resistant to 2,4-D and 2,45-T; l to 2 lbs. 2,4·D per acre at pre-bud stage will stop seed production l lb. 2,4-D Russian thistle (A) l lb. 2,4-D ester Sand sagebrush (P) \12 to l lb. 2,4-D Shepherd's purse (FA) 1 to 2 lbs, 2-4·D Smartweed (A) 1 lb. 2,4-D Snow-on-the-mountrain (A) Soapweed (Yucca) (P) !lb. 2,4,5-T ester in 10 gal. diesel oil applied as wetting spray 1 lb. 2,4-D Stiffleaf goldenrod (P) 1 to 2 lbs. 2,4-D ester or Sumac (P) amine, full foliage Sunflower (A) \12 to l lb. 2,4-D l to 2 lbs. 2,4-D Tanweed (P) Thistles (except Canada) l lb. 2,4-D Velvetleaf (A) Vervain (P)

I lb. 2,4·D

Water hemlock (P) Wild rose (P) Yarrow (P)

2 lbs. 2,4·D ester 2 to 3 lbs. 2,4,5 -T es ter I to 2 lbs. 2,4-D

Yellow goatsbeard (B) Yucca (P)

1 lb. 2,4-D (See Soapweed)

I to 2 lbs. 2,4-D

Time to Treat

Prior to bloom; kills most vegetation Early summer Late fall or early spring (late March or early April) before bloom Early spring Before the bud stage Late spring or early summer Early spring Late spring or early summer Early summer, for 2 or more years Early summer Apply sterilants in spring or fall Late spring Late May or early June Early spring Late spring or early summer Early summer In mid·spring Late fall or early spring Late spring Late spring or early summer Late spring; repeat when 8 to 10 inches growth appears; trea t 2 or more years Late fall on rosettes or in spring before flower stem lengthens Late spring or early summer Late spring; trea t for 2 or more yea rs Befo re the bud stage Late spring or early summer Late spring; treat 2 or more years Late spring

The weed control materials suggested in Table I are not harmful to animals when used as suggested. However, the chemicals could cover up objectionable characteristics of plants usually avoided by livestock. This could cause an animal to eat forage he normally avoids.

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Mowing For many years our standard recommendation for weed control in pasture has been mowing at a time when the weed has exhausted most of its reserves. For most plants this critical period is from the bud to early-bloom stage. The theory behind this practice is to destroy the plant parts which manufacture food at the time when the food supply stored in the roots from the previous year is lowest. This results in r educed vigor and eventual death of the plant. Recent research by the Agricultural Research Service and University of Nebraska Agricultural Experiment Station (1950-1959) shows us the following facts about mowing as a means of controlling weeds in the pasture. l. Mowing resulted in a decrease of total forage production from the pasture. 2. At best, mowing gave only a decrease in vigor of most weeds. Satisfactory control was not obtained on any species of perennial pasture weeds. 3. Some annual weeds were satisfactorily controlled by mowing in early July.

Reseeding Plowing and reseeding is an ideal way to handle the weed situation in a weedy pasture if it can be farmed for at least one year. Grow small grain, sudan, sorghum, or similar crops for one or more years on the plowed-up pasture. You can then make seedings directly into the stubble without additional seedbed preparation, providing the stubble is relatively free of weeds and volunteer growth. In many instances it may be advisable to subsurface till, oneway, or disk to kill weeds and volunteer growth prior to seeding. Remember, a good seedbed is firm. Rolling or packing must follow any tillage operation for seedbed preparation. 6

Advantages of Reseeding l. You do a more thorough and effective job of controlling weeds. 2. You replace undesirable plants with desirable grasses and legumes. 3. Your renovated pasture will be more productive than the old pasture.

Management

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You will favor your grass and discourage weeds by following these simple rules: l. Don't put too many livestock in your pasture. 2. Give the pasture a good rest once in a while. 3. Conserve moisture by leaving two to four inches of growth on short growing grasses and four to eight inches on taller species. This helps prevent run-off and reduces evaporation. 4. Fertilize and apply lime if your pasture needs it. 5. Graze cool-season grasses in the spring and fall and warm-season grasses during the summer months. Native warm-season grasses-big bluestem, switchgrass, sand lovegrass, sideoats grama, little bluestem, buffalo, and blue and hairy grama-will produce the best forage during the hot summer months. To maintain these grasses in a high state of productivity it will be necessary to delay grazing them until mid-June or early July. This also means you will have to provide forage for early spring grazing. Rye and vetch, other small grain, and second-year sweetclover will give you early temporary pasture. Cool-season plants such as bromegrass, intermediate wheatgrass, and crested wheatgrass with alfalfa, trefoil, or sweetclover provide excellent permanent pasture for spring and fall grazing. In eastern Nebraska many of the warm-season grasses have been replaced by bluegrass. If you have such a pasture, it may be best to manage it as a cool-season pasture. Use fertilizers and try to introduce such legumes as Korean lespedeza or birdsfoot trefoil into the bluegrass. They will increase the benefits of the weed control program. If your pastures are principally cool-season grasses, you may need to provide extra forage during the hot summer months. Sudan grass is our best annual grass for supplemental grazing during July and August. Perennial warm-season grasses may be used as permanent pasture to provide forage during the summer. Keep in mind-the effectiveness of any weed control program depends upon the management practices you are willing to follow with regard to stocking rates, proper season of use for different grasses, moisture conservation, and lime and ferti lizer use. High producing pastures free of weeds don't just happen. They are a result of good pasture management.

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This circular is a publication of the Pasture Improvement Committee of the Nebraska College of Agriculture. It was prepared by John Furrer and Don Burzlaff with assistance from M. K. McCarty and Paul Sand. Other circulars in this series on Productive Pastures: CC 164 Using Temporary Pastures CC 165 Establishing Pastures in Nebraska CC 166 Choice of Perennial Grasses for Forage Production and Erosion Control CC 167 How to Use Pastures CC 168 Green Chop Feeding CC 169 Does it Pay to Improve Your Pastures? CC 170 Irrigated Pastures CC 174 Sudangrass for Summer Pasture

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Your COLLEGE OF AGRICULTURE has several BRANCH OFFICES The College of Agriculture of your University of Nebraska has a "local office'· convenient to you, where ever you may live in this wide state. These "local offices," of course, are the County Extension offices in most Nebraska counties. There also are the "branch offices" of the Experiment Stations at Ft. Robinson, North Platte, Mitchell, Alliance and Concord. Your County Agent has a wide variety of free bulletins written by Nebraska agricultural scientists and directed at Nebraska conditions and problems. We urge you to use your County Agent and your County Home Agent. They are there to serve you. Dean W. V. LAMBERT, College of Agriculture University of Nebraska.

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